As for the different color Nintendo usually shows their later consoles in a number of color some find there way into the market place (Japan, ie Spice Gamecube) some never see the light of day.) The red and green were color that were first introduced in the prototype they showed at E3, so maybe this would be a good sign that none of the colors have been droped.
On a side note it really doesn't cost that much more to change the colors of the outside shell, since they could do multiple colors of the system on one assembly line. (Doing every one which is common in some setups, and having the machines differenciate by serial or do it by handle at the end of the line.)